Aug. 1, 2017

Astronomy for the people: The Rothney Astrophysical Observatory

UCalgary's Rothney Astrophysical Observatory does more than provide a view into space – it makes the universe accessible to the community.

Perched on a hilltop just south of Calgary is a “dark skies” observatory for viewing celestial wonders and training University of Calgary students in astrophysics.

The university’s Rothney Astrophysical Observatory (RAO), near Priddis, in the foothills of the Rocky Mountains, is equipped with one of the country’s largest telescopes along with an array of specialized smaller telescopes and instruments.

“A star-filled nighttime sky is a natural resource that everybody should have the right to, just like clean water and clean air. It’s a natural resource that we forget about,” says Phil Langill, senior instructor in the Department of Physics and Astronomy in the Faculty of Science, and director of the RAO.

The observatory is more than a working scientific facility.

Through its public outreach programs, the RAO helps many families, students and community groups discover something they’d literally lost sight of – truly dark skies.

“Some of them have not seen a sky like that,” says Jennifer Howse, the RAO’s education specialist.

“I’ve had kids come back years later and tell me what an exciting experience it was to be able to look through a telescope late at night, and maybe see Saturn or a globular cluster or something they had only read about.”

The RAO’s original, 50-year-old, 0.41-metre Clark-Milone Telescope (named after the observatory’s original directors) can measure very small variations in the brightness of stars.

With this optical telescope, UCalgary astrophysics students have been able to observe and confirm the transit of “exo-planets” orbiting around two stars in our Milky Way galaxy.

The precision required to make such measurements is akin “to driving at night and a mosquito passes in front of the headlights of a car 10 kilometres away coming toward you, and detecting the subsequent very tiny dip in brightness,” Langill says.

The Clark-Milone Telescope (CMT) also has a ‘piggy-backed’ telescope which directs light to a sensitive, high-resolution spectrograph instrument. Students have used it to confirm the presence of the chemical element bromine in the spectrum of Jupiter, and measure the rotation speed of the Sun, Jupiter, and Saturn’s rings.

 Operated remotely from campus via the Internet, the CMT is key to the observatory’s “Universe in Classroom” educational program for science teachers and their students.


Rob Cardinal, an Indigenous Blackfoot Cree astronomer, discovered an asteroid and two comets while working as a research associate at UCalgary.

Langill says Cardinal used the observatory’s wide-field-of-view Baker-Nunn Telescope, made by U.S. Air Force. It was originally employed during the Cold War and installed at Canadian Forces Base in Cold Lake, Alberta, to find and track Soviet satellites. After the telescope was no longer needed by the military, RAO researchers acquired and refurbished it. It is now used to observe faint objects, such as distant galaxies.

Howse, who has an undergraduate degree in Aboriginal history and a graduate degree in museum studies, notes that the nighttime sky “was so much a part of Aboriginal people’s psyche, their spirituality, their directions, the changing of the seasons – everything to do with their lives.”

She incorporates the Aboriginal perspective in the RAO’s public programming, including a section on the website titled “First Nations Sky Lore.”

The RAO’s largest telescope, the A. R. Cross Telescope, has a 1.83-metre-diametre mirror. Designed and built at UCalgary in the early 1980s, the telescope is named after rancher Arthur (“Sandy”) Rothney Cross, who donated land to the university for the observatory as well as funding to build the instrument. The telescope originally measured infrared radiation, which can reveal characteristics of the environment around stars.

The RAO has a 2,200-square-foot, wheelchair-accessible interpretive centre. It includes state-of-the-art classroom facilities, an outdoor amphitheatre area, and educational displays about astronomy and space science.

Howse says the facility receives about 12,000 visitors a year on average, and can get about 800 over one evening during the popular “Milky Way Nights” events in July and August.

Everything the RAO does relies on dark skies. There is concern that the new ring road, being built southwest of Calgary, will bring expansion and unnecessary lighting that interferes with the observatory’s scientific, teaching and public outreach work.

The Alberta government, which is responsible for the ring road, is aware of the concerns, and will use more modern, downward-pointing lighting along the road’s new sections, Langill says. “I think if people just try to use light smartly, there are many more years of life for the observatory.”

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Phil Langill is a senior instructor of Astronomy and Physics in the Faculty of Science at UCalgary and the director of the Rothney Astrophysical Observatory (RAO). View Phil's publications

Jennifer Howse is an education specialist at the University of Calgary’s Rothney Astrophysical Observatory (RAO) . She develops and delivers school programming to educate students, school groups, and the public about the wonders of astronomy.

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